Various devices and methods for moulding plastic preforms into plastic containers have been known from the prior art for some time. It is normal in the prior art first generate these plastic preforms in a blow moulding process and then fill them with a fluid, in particular a drink. Also different variants of this filling process are conceivable. Thus for example so-called cold filling is possible, wherein it is particularly relevant that the containers produced are pressure-resistant. Furthermore a method of hot filling is known from the prior art, i.e. in this method the drinks are poured into the containers in a greatly heated state. In this method the containers must be vacuum-resistant as on cooling of the bottle, the volume reduces. This bottle must be able to compensate for this volume reduction. Thus normally with this filling method, the bottle weight of the preform is higher than in cold filling.
U.S. Pat. No. 4,276,987 discloses a hollow body made from a thermoplastic material. EP 0 244 128 describes blow-moulded containers. A central area of these containers is fitted with a recess which is formed by a peripheral wall and base wall.
In a method used internally by the applicant, the containers are filled with medium at a temperature of 85° C. for example, then pressurised with nitrogen and sealed. Immediately after sealing the pressure in the bottle rises. It must firstly be guaranteed that the container does not deform during the filling phase with hot medium, and after sealing the container must be able to compensate for a pressure of for example up to 2 bar. However according to the prior art the problem arises here that the base can bulge, clearly reducing the base clearance present in the container, which again can mean that the containers wobble or stand tilted.
It may be desirable to provide devices and methods for production of plastic containers which simplify subsequent hot filling of the container.